Some patients are impaired in their gastroenteric functions to have poor digestion, so it is sometimes necessary to inject intravenous medical solutions such as dextrose solutions, specifically prepared liquid medicines, or other injectable solutions contained in solution packs or bottles, into a vein of a patient using an intravenous drip unit.
During injection of specific intravenous medical solutions, such as liquid anticancer drugs or liquid antibiotics, into the veins of infant patients or other persons who are seriously ill, it is necessary to continuously inject the solutions into the veins at constant flow rates determined in accordance with the physical conditions of the patients.
When the injection of specific medical solutions into the veins is performed while failing to continuously inject the solution into a vein at a constant flow rate determined in accordance with the physical condition of a patient, there is a danger of shock or injury to the patient due to incorrectly supplied dosage of he medical solution.
An intravenous drip unit, or a so-called “clamp”, which has been used in injection of an intravenous medical solution, for example, Ringer's solution, specifically prepared liquid medicines, or other injectable solutions, into a vein of the patient, typically comprises a solution container containing the medical solution, a hose hermetically extending from the lower end of the container to a predetermined length, a solution flow confirming member mounted to an intermediate position of the hose to allow a user to confirm the flow rate of the solution, a needle mounted to the outside end of the hose so as to inject the solution into the vein, and a solution flow regulator mounted to the hose at a position between the solution flow confirming member and the needle to allow the user to regulate the flow rate of the solution flowing to the needle as desired.
In order to inject a medical solution into a vein of a patient using such an intravenous drip unit, a user, for example, a nurse, inserts the needle of the drip unit into the vein, and controls the solution flow regulator to regulate the flow rate of the solution in the hose, thus allowing the solution to be injected into the vein at the regulated flow rate.
Such a conventional solution flow regulator is typically designed such that a user rotates the regulator upward or downward to control the sectional area of the hose, thus regulating the flow rate of the solution. The hose is typically made of a soft plastic or rubber material, and so the regulator may fail to finely regulate the flow rate of the solution after repeated use over a lengthy period of time.
In addition, several types of solution injectors designed to automatically regulate the flow rate of an intravenous medical solution during an injection have been proposed and widely used for medical applications.
However, such an injector is expensive, and must be used with an additional intravenous drip unit, so that the injectors are inconvenient to users while storing and managing the injectors. Another problem of the injectors resides in that they often malfunction and are easily broken, so that the injectors may unexpectedly stop injection of a solution into a vein, or inject the solution into the vein at an excessive flow rate, or forcibly inject the solution into the vein to cause a danger of shock or injury to the patients.